HRS在硫磺制酸中的应用

重点介绍 HRS 的工艺原理、特点、主要设备及在中国 2 套硫磺制酸装置上的应用情况.HRS 用 HRS 热回收塔取代传统工艺的吸收塔,用 HRS 锅炉取代传统工艺的吸收塔酸冷却器,从而使硫酸装置的总能量回收率从传统装置的 70% 提高到 93%,同时减少了循环冷却水消耗,其经济效益、环境效益显著.     

屏蔽泵在硫磺制酸中的应用

本文主要介绍硫磺制酸中输送液体硫磺的屏蔽泵的结构特点,及其安装,运行中应注意的事项。     

屏蔽泵在硫磺制酸中的应用

本文主要介绍硫磺制酸中输送液体硫磺的屏蔽泵的结构特点,及其安装、运行中应注意的事项。     

碳化硅／碳复合材料的特性及其应用

用涂层和其他表面改性处理方法制取的碳化硅/碳复合材料兼有碳化硅的硬度高、耐热性、抗磨损、腐蚀和碳素材料可加工性等优良 性,在滑动摩擦材料,电子元件热处理用夹具、单晶硅提拉用加热器、坩埚硅片外延生长用感受器、高温材料等方面获得了广泛应用,其应用范围不断扩大,被誉为划时代的新材料,东新电碳公司于1983年研制成功硅化石墨T1056,其各项技术性能指标已达到国外同类产品水平,目前已批量生产,为我国的科研和工业生产提供了高性能材料。     

屏蔽泵在硫磺制酸系统中的应用

我公司于1998年由硫铁矿制酸改为硫磺制酸,其主要原料为镇海炼油厂的炼油副产品液硫, 液硫泵选用的是日机装公司生产的高融点型屏蔽泵。当时国内使用该型号泵的厂家很少,所以这样做具有一定的风险。但因为当时日机装的 SGM型屏蔽泵在我公司用于输送成品硫酸效果很好,解决了我公司长期以来在采用陶瓷泵、拉波泵等泵时存在的部件易损、外泄、维修费高等问题,所以我们决定一试。结果,效果同样很好。     

莫来石结合碳化硅制品的研制

以微粉技术合成的莫来石为结合相,经低温烧成研制的碳化硅制品,具有优异的高温强度和导热性能,而且制品不氧化,使用寿命长。     

热管锅炉在硫磺制酸中的应用

介绍热管和热管锅炉的工作原理、性能参数和硫磺制酸中应用情况。     

热管省煤器在硫磺制酸中的应用

在硫磺制酸装置中,转化工段带走的中低温废热得到了有效回收,提高了整个装置的经济效益。但传统的列管省煤器由于低温腐蚀及设备结构形式的不合理,存在着故障率高、使用寿命短、换热效果差等问题。针对硫酸生产工况的恶劣环境,我厂开发研制了以重力热管为主要传热元件的热管省煤器。     

SiC/Si上六方YMnO3薄膜的制备和铁电性能

采用化学溶液法在 SiC/Si 上制备了YMnO3 薄膜.XRD 结果显示所制备的薄膜为六方YMnO3,且具有部分择优取向生长.拉曼光谱和XPS的结果验证了样品为六方纯相YMnO3.以 Pt 为顶电极,测试了 YMnO3 薄膜的电滞回线,结果显示YMnO3 薄膜具有良好的铁电性质.     

Electrical properties of biomorphic SiC ceramics and SiC/Si composites fabricated from medium density fiberboard

A study has been made of the dependences of the electrical resistivity and the Hall coefficient on the temperature in the range 1.8-1300 K and on magnetic fields of up to 28 kOe for the biomorphic SiC/Si (MDF-SiC/Si) composite and biomorphic porous SiC (MDF-SiC) based upon artificial cellulosic precursor (MDF - medium density fiberboards). It has been shown that electric transport in MDF-SiC is effected by carriers of n-type with a high concentration of ∼10²⁰ cm⁻³ and a low mobility of ∼0.4 cm² V⁻¹ s⁻¹. The specific features in the conductivity of MDF-SiC are explained by quantum effects arising in disordered systems and requiring quantum corrections to conductivity. The TEM studies confirmed the presence of disordering structural features (nanocrystalline regions) in MDF-SiC. The conductivity of MDF-SiC/Si composite originates primarily from Si component in the temperature range 1.8-500 K and since ∼500 to 600 K the contribution of MDF-SiC matrix becomes dominant.     

酸碱处理对SiC粉体表面性质的影响研究

本文建立了一种对SiC表面羟基浓度定量检测的方法,利用卡尔费休微量水分测定仪直接测量出SiC表面羟基浓度.经计算,本方法RSD为3.8％,对于SiC粉体表面羟基浓度测定能够得到满意的结果.通过X射线能谱仪(EDS)进行表面元素分析,表明酸碱处理使SiC粉体表面碳硅比趋向于符合化学式的1∶1.测量相同固相含量的SiC浆料粘度,数据表明经过酸碱处理过的SiC粉体使相同固相含量的浆料粘度降低.改变浆料的pH值可改变其粘度,找到了使SiC粉体流变性能最适宜的pH值.     

SiC浆料的流变性能研究

为制备结构均匀的多孔SiC陶瓷的料浆,本文比较了不同质量分数(40%~60%)的SiC浆料的剪切应力和黏度随剪切速率的变化.结果表明:浆料的等电点在3.6左右,Zeta电位值随着pH值的增加而减小,碱性环境下分散效果更好;用Casson方程拟合浆料的剪切应力,相关系数在0.98以上,随着固相含量的增加,拟合的极限粘度和屈服应力增加;当剪切速率达到100 s-1时,固相含量为40%~55%浆料的粘度都在1 Pa·s以下,固相含量为60% 的浆料粘度大概是2.1 Pa·s.     

黄杨木制备SiC木质陶瓷的性能与表征

SiC木质陶瓷是近年来应用前景广阔的新型陶瓷材料,以绿色可再生的木材为原材料,通过反应烧结工艺制备出的陶瓷具有优良的高温力学性能。为探究影响生物质陶瓷性能的因素,将黄杨木在800 ℃氮气保护下热解形成生物质炭坯,然后在1 650 ℃和1 900 ℃两种高温下进行熔融渗硅制备SiC木质陶瓷。利用X射线衍射仪(XRD)和扫描电子显微镜(SEM)研究SiC木质陶瓷的物相组成和微观结构,采用阿基米德排水法和三点弯曲法测定陶瓷的开孔率、密度和弯曲强度,再使用维氏硬度计测定SiC木质陶瓷的显微硬度。研究结果表明:在1 650 ℃下通过熔融渗硅可以得到微观结构均匀的SiC木质陶瓷,在1 650 ℃比在1 900 ℃下熔融渗硅制备陶瓷的力学性能更优异,陶瓷的密度更大,为2.27 g/cm³,此时弯曲强度为192.45 MPa;游离Si会提高SiC木质陶瓷的密度,增强陶瓷的弯曲强度。     

Si/SiC coated Cf/SiC composites via tape casting and reaction bonding: The effect of carbon content

In this paper, a novel surface modification method for C_f/SiC composites is proposed. Si/SiC coating on C_f/SiC composites is prepared by tape casting and reaction bonding method. The effects of carbon content on the rheological property of the slurries along with the microstructure of the sintered coatings are investigated. The best result has been obtained by infiltrating liquid silicon into a porous green tape with a carbon density of 0.84 g/cm³. In addition, the effect of sintering parameters on the phase composition of the coatings is studied. Dense Si/SiC coating with high density as well as strong bonding onto the substrate is obtained. This Si/SiC coating exhibits an excellent mechanical property with HV hardness of 16.29±0.53 GPa and fracture toughness of 3.01±0.32 MPa m^1/2. Fine surface with roughness (RMS) as low as 2.164 nm is achieved after precision grinding and polishing. This study inspires a novel and effective surface modification method for C_f/SiC composites.     

Thermal plasma synthesis of Si/SiC nanoparticles from silicon and activated carbon powders

In this study, Si/SiC nanocomposites were synthesized by non-transferred arc thermal plasma processing of micron-sized SiC powder. First, micron-sized SiC was synthesized by solid-state method where waste silicon (Si) and activated carbon (C) powder were used as precursor materials. The effect of Si/C mole ratio and solid-state synthesis temperature on structural and phase formation of SiC was investigated. Diffraction pattern confirmed the formation of SiC at 1300 °C. High C content was required for the synthesis of pure SiC as Si remained unreacted when Si/C mole ratio was below 1/1.5. Highly agglomerated micron-size (0.6–10 µm) SiC particles were formed after solid-state synthesis. Thermal plasma processing of solid-state synthesized micron-sized SiC resulted into the formation of uniformly dispersed (20–60 nm) Si/SiC nanoparticles. It was proposed that Si/SiC nanocomposites were formed due to partial decomposition of SiC during high temperature plasma processing. The formation of Si/SiC nanoparticles from micron-sized SiC was resulted from dissociation of grains from their grain boundary during plasma processing.     

Preparation and properties of SiC/SiC-SiYC with excellent water-oxygen corrosion resistance

In this study, the SiC/SiC-SiYC composites were fabricated via chemical vapor infiltration (CVI) combined with the reactive melt infiltration (RMI) process. The excellent infiltration of Si-Y alloy assisted in fabricating composites with a density of 2.94 g/cm³ and a porosity of only 2.0%. After 20 h of corrosion at 1300 °C in the water-oxygen environment, the generated oxide layer, consisting of a glass layer and a diffusion layer, effectively protected the composites, and the flexural strength retention is 114.2%. This study highlights the significant potential of Si-Y alloy as a modification phase that is resistant to water and oxygen. It also presents a novel approach for developing high-density ceramic matrix composites that are resistant to water-oxygen corrosion.     

高固含量SiC浆料流变性能的研究

本文研究了高固含量的SiC浆料的流变行为。研究发现,由于表面被氧化使得其等电点与SiO2接近,浆料的流变行为基本符合幂律流体,用强碱性分散剂效果好于中性分散剂。     

SiC反射镜表面改性研究进展

采用SiC陶瓷作反射镜是目前国际上的一个研究热点。但是SiC陶瓷用作反射镜时存在各种类型的缺点,必须对SiC反射镜表面进行改性。本文综述了各种表面改性方法、制备机理以及优缺点,最后展望了未来SiC反射镜的发展方向：即低成本化和大型化。